1. Field of the Invention
The invention relates to a moving body position detection system, a moving body position detection apparatus, a moving body position detection method, and a computer-readable storage medium for detecting the position of a moving body.
2. Description of the Related Art
Recently, a navigation device that provides a vehicle with traveling guidance is mounted in many cases in the vehicle to allow a driver to easily arrive at a desired destination. A navigation device uses a GPS receiver to detect the current position of a host vehicle, acquires map data, corresponding to the current position, from a recording medium such as a DVD-ROM or an HDD or from a network, and displays the acquired data on a liquid crystal monitor. In addition, the navigation device has the route search function that searches for an optimal route from the starting point to the destination in response to a destination input by the driver. The navigation device displays a guidance route, which is selected based on the search result, on the display screen. In addition, when the vehicle approaches a junction where guidance on right turn or left turn is necessary (hereinafter called a guidance junction), the navigation device gives a guidance via voice or a display screen to guide the user to a desired destination. Recently, some of the mobile phones, smartphones, Personal Digital Assistants (PDA), and personal computers have a function similar to that of the navigation device described above. In addition, the guidance described above may be given not only to a vehicle but also to a pedestrian or a bicycle.
When a vehicle approaches a guidance junction where guidance such as a right or left turn instruction is given, it is important to give such guidance with right timing. Giving guidance with right timing requires the accurate detection of the vehicle's current position. The accurate detection of the current position of a vehicle is important not only for giving guidance on a guidance junction but also for controlling the vehicle (for example, decelerating the vehicle) when the vehicle approaches a junction.
One of the conventionally known methods for detecting the vehicle's current position is a dead reckoning navigation that relatively detects the vehicle's current position using the information (dead reckoning navigation information) obtained from a distance sensor or an angle sensor mounted in the vehicle. However, the method for relatively identifying the vehicle's position from the dead reckoning navigation information used in a dead reckoning navigation cannot accurately detect the vehicle's current position when the vehicle travels on a road with a special shape such as a curved road or a rotary. To solve this problem, Japanese Patent No. 4651511 proposes a technology for accurately detecting the vehicle's current position by detecting the turning angular amount relative to the base point of the rotary when the vehicle passes through a rotary.